Rotary take-up for sewing machines



May 22, 1951 R. HOFFMEISTER v 2,554,144

ROTARY TAKE-UP FOR SEWING MACHINES Filed July 30, 1948 4 Sheets-Sheet 1 I Robrt flyrneiszfer Wilmeaia: 1 w I Etta meg May 22, 1951 R. L. HOFFMEISTER ROTARY TAKE-UP FOR SEWING MACHINES 4 Sheets-Sheet 2 Filed July 50, 1948 Robert LHbj/me'ster gnvewboz/ jme /5 atbomaw May 22, 1951 R. L. HOFFMEISTER ROTARY TAKE-UP FOR SEWING MACHINES 4 Sheets-Sheet 3 Filed July 30, 1948 gm'v e ntoe Robert L. [[0 mea'ster y 1951 R. L. HOFFMEISTER ROTARY TAKE-UP FOR SEWING MACHINES 4 Sheets-Sheet 4 Filed July 30, 1948 Patented May 22, 1951 UNITED STATES PATENT OFFICE ROTARY TAKE-UP FOR SEWING MACHINES Robert L. Hoffmeistcr, Westfield, N. J., assignor to The Singer Manufacturing Company, Elizabeth, N. J., a corporation of New Jersey Application July 30, 1948, Serial No. 41,472

13 Claims. (01. 112-248) This invention relates to a needle-thread takeup for sewing machines, and more particularly to a rotary type take-up in which a pair of rotary elements having fixed axes of rotation are utilized to satisfy the thread-handling requirements of high speed, lock-stitch sewing.

It is one feature of the invention to provide a double rotary take-up which may be operated in conjunction with a strong check-spring plus a heavy frictional drag or tension applied to the needle-thread by the tension device. The ability of the check-spring to recover from any one of its stressed or displaced positions in time to perform the next succeeding thread-controlling operation is directly proportional to the spring strength. The use of a heavy check-spring necessarily involves the use of a heavy tension in order to discourage stealing by the check-spring of unwanted thread from the supply through the tension device.

The use of a strong check-spring and heavy tension in combination with a double rotary takeup is made possible by this invention which establishes a secondary thread-tensicning effect in the take-up itself, countering that of the regular tension device at specific intervals in the stitchforming cycle. The secondary tension acts against the regular tension device to assist the take-up in pulling the required amount of thread through the tension device at the stitch-setting point, and simultaneously acts to relieve some of the tension on the thread-limb leading from the take-up to the work, the latter function tending to preclude the possibility of puckering of the seam due to overtensioning of the thread leading thereto. The secondary tensioning effect in a double rotary take-up is created by a new orientation of the component parts thereof, and also involves changes in the direction of rotation of the thread-engaging members.

The introduction of a secondary thread-tensioning force by the take-up in the direction of lead of the thread from the tension device to the needle gives rise to a problem in thread handling, the elimination of which constitutes a second part of this invention. In placing a frictional drag by means of the take-up on the needlethread after it emerges from the primary tension device and in a direction toward the needle, there is a tendency to build up slack thread between the take-up and the needle. This condition is detrimental to efiicient sewing, particularly at that point in the stitch-forming cycle at which the needle first penetrates the work on its .descending stroke prior to forming the stitch. At

this point it is possible for the slack thread. to become fouled beneath the tip of the needle resulting in thread breakage. It is one of the features of this invention to provide an effective means cooperating with the take-up to prevent the slack thread from reaching the needle just prior to the point in the stitch forming cycle at which the needle penetrates the work.

A still further feature of the invention is the provision of an effective thread-breaking means whereby abnormal winding fo the needle-thread about the revolving thread-engaging members of the take-up is precluded, and which provides means for retracting the breaking pins from their operative positions for the purpose of gaining access thereto to facilitate removal of entangled thread pieces.

A preferred embodiment of the invention 11-- lustrating the above, as well as other features, is described in the ensuing specification referring to the accompanying drawings in which:

Fig. 1 is a longitudinal vertical sectional View of a single needle, lock-stitch sewing machine incorporating the new take-up.

Fig. 2 is a head-end elevation of the sewing machine showing the orientation and direction of rotation of the take-up disks, and includes the anti-winding device shown in its operative position.

Fig. 3 is a also a head-end elevation of the sewing machine showing a portion of the coverplate of the take-up broken away to reveal the thread-engaging pins thereof acting upon the needle thread. The thread-engaging pins are shown in two different positions in the stitchforming cycle; the dotted lines ShOWing the pins substantially at the point at which the needle is penetrating the Work and the full lines showing the pins at the stitch-setting point.

Fig. 4 is a cross-sectional view of the bracketarm of the sewing machine taken along the line 4-4 of Fig. l and shows the driving mechanism for the rotary take-up shafts.

Fig. 5 is a sectional view taken along the line 55 of Fig. 2 and shows in full lines the antiwinding device in its operative position, and in dotted lines the anti-winding device in its retracted or inoperative position.

Fig. 6 is a sectional View taken along the line 6-6 of Fig. 2 and again shows the anti-winding device both in its operative and inoperative positions.

Fig. '7 is a head-end elevational view of the sewing machine showing a modified form of the thread-breaking device.

Fig. 8 is a view of the modified form of the thread-breaking device shown in Fig. '7 taken substantially along the line 88 thereof.

The sewing machine embodying the invention comprises a conventional frame including a bedportion l upon which is seated an upright standard 2 which in turn carries a horizontal hollow bracketarm 3. Rotatably journaled in the bracket-arm 3 is an arm-shaft 4 which is actuated by a belt-driven balance wheel 5. The arm shaft 4 reciprocates a needle-bar 6 by means of a crank I and connecting link 8. An eye-pointed needle 9 is secured to the lower end of the needlebar 6. Mounted adjacent the needle-barfor longitudinal movement is a presser-bar' l having a presser-foot ll afiixed to its lower end,

The arm-shaft 4 also drivesa vertically disposed rotary shaft l2 through a pair of bevel gears 13. Ihe vertical shaft l2 in turn drives a rotary hook-shaft l4 horizontally disposed Within the bed portion l of the sewing machine, the driving connection between the two shafts comprising a pair of bevel gears l5. A rotary hook I6 is secured to the end of the hook-shaft l4 and is driven in a 2:1 speed ratio relatively to the arm shaft 4.

A feed-advance eccentric l1 and a feed-lift eccentric l8 are also carried by the arm-shaft 4. Surrounding the respective eccentrics are vertically disposed pitman links [9 and 2B which oscillate rock-shafts 2| and 22 within the bed of the sewing machine. Rock-arms 23 and 24 (Fig. 2) are secured to the rock-shafts 2i and 22, respectively, and impart the usual four-motion feeding movements to a feed-bar 25 to which is affixed a feed-dog 26.

The take-up mechanism includes a pair of parallel, rotary shafts 21 and 28 journaled in the head-end of the arm 3, both being driven by an arm-shaft gear 29 through gears 30 and 3!, respectively (Fig. 4). A disk 32 is aflixed to the end of the shaft 21 which is driven in a 2:1 speed ratio relatively to the arm-shaft. A disk 33 is secured to the end of the shaft 28 which is driven in a 1:1 speed ratio relatively to the armshaft. The disk 32 carries a single thread-engaging member or pin 34. The disk 33 carries a pair of circumferentially spaced thread-engaging pins and 36. An apertured cover-plate 39 affixed to the frame of the sewing machine overlies the take-up disks.

The take-up is threaded by passing the thread T from the supply through stationary thread guides 3'! and 38, into the tension device 40, over a check spring 52 adapted to yield in a counterclockwise direction about the tension device, under a stationary guide or pin 43, and over the thread-engaging pins of the take-up, starting with the pin 34 of the forward disk 32, and then leading rearwardly over the pins 35 and 36 of the rear disk 33. From the rear disk the direction of the lead of thread is reversed, returning forwardly toward the operator, as well as downwardly to be engaged by a thread-guide 44 disposed beneath the forward take-up disk 32. After rounding the guide 44, the thread passes downwardly through a guide 45 to the eye of the needle 9.

Referring to Fig. 3, the thread-engaging pins of the take-up are shown in two different positions in the stitch forming cycle. As shown in full lines, the pins are disposed approximately in their stitch setting positions. In this vicinity it is incumbent upon the take-up device both to set the stitch in the work and to pull a small quantity of thread from the supply through the tension device, this quantity being equal to that used up in forming one stitch. The tension device is required to exert a frictional drag upon the thread sufficiently strong to constrain free movement of thread from the supply, which free movement would prevent the take-up from properly setting the stitch in the work. On the other hand this resistance to the movement of the thread must not be so excessive as to cause puckering in the seam or to prevent the take-up from pulling off from the supply the required quantity of thread with which to form the next succeeding stitch. Thus there is an inherent maximum and minimum limitation in the magnitude of the frictional drag which may be applied to the thread in any given lockstitch sewing machine.

It is possible, however, for an otherwise satisfactory tension in the needle-thread to be so light that slight irregularities in the sewing conditions, i. e., variations in the thickness or density of the work, imperfections in the thread etc., may create a temporary frictional drag on the sewing thread which would cause stealing of unwanted quantities of thread from the supply at any one of several points in the stitch-forming cycle. The use of light tensions, furthermore, necessitates the use of a correspondingly weak check-spring for the reason that a check-spring is required to yield at certain critical points in the stitch-forming cycle to provide, momentarily, extra quantities of lightly tensioned thread, and the reluctance of a check-spring to yield to this demand would raise the tension on the thread and en courage stealing. A strong check-spring, on the other hand, is desirable in high-speed sewing machines for the reason that its ability to recover rapidly from its stressed or displaced position to be ready to perform its next operation is directly dependent upon its spring strength. Thus, ideally, a sewing machine operating at high speeds utilizes a strong check-spring and hence a heavy tension.

By means of this invention it is possible to op erate a sewing machine using a strong checkspring and heavy tension in conjunction with a double rotary take-up without jeopardizing the quality of the stitch. This is accomplished by establishing at specific intervals in the stitchforming cycle a frictional drag or secondary thread-tensioning effect in the take-up itself. This force counters in direction that of the primary tension device, thereby to supplement the take-up in its function of pulling the required thread through the tension device, and also to relieve a portion of the tension on the threadlimb leading from the take-up to the seam at the time of stitch setting.

To effect this secondary tensioning force in the take-up, the orientation and direction of rotation of the rotary elements of the take-up have been so arranged that relative motion is established between the thread and the thread-engaging pins at the'time of stitch-setting. The direction of this relative motion is such that a frictional. drag is put upon the thread opposing that of the tension device. As seen in Fig. 3 the direction of rotation of the take-up disks is counterclockwise, and is such that the movement of the thread-engaging pins is in the direction of the flow of thread from the tension device to the needle for the major part of the stitchforming cycle. At the point of stitch-setting the frictional drag of the thread-engaging pins upon the thread acts to relieve a portion of the tension upon the thread-limb leading to the seam. Thus the full load of the tension device is not carried to the seam, but a portion of the force is dissipated in the take-up, which force is utilized to assist the take-up in pulling required thread from the supply through the tension device.

This advantage in the thread-handling characteristics of the new take-up at the stitch-setting point would ordinarily be outweighed by the occurrence of slack in the thread-limb leading to the needle in a subsequent point in the stitch forming cycle called penetration. The point of penetration is by definition that point at which the eye of the needle passes through the work on its descending stroke. The positions of the thread-engaging pins of the take-up at this point are shown in dotted lines in Fig. 3. In moving counterclockwise from the stitch-setting point the movement of the thread-engaging pins con" tinues in the direction of lead of the thread to the needle, and in so doing has a tendency to build up slack-thread between the take-up and the needle. This slack thread, if permitted to find its way to the tip of the needle could result in fouling of the thread just prior to penetration. The consequence is thread breakage. To obviate this condition the thread-guiding element as has been interposed between the take-up and the needle. This thread-guide is laterally spaced from the thread-engaging pins of the disk 33 at the time that the needle is approaching the penetration point, so that the thread-limb between the pins of the disk 33 and the guide 44 is disposed substantially horizontally. The force of gravity along the length of this thread-limb, inertia or whipping action of the thread-limb as it is displaced laterally, and the retarding frictional force of the thread as it rounds the stationary guide combine to establish a bellying action in the thread-limb which uses up the slack and thus maintains the preceding thread, which is disposed between the guide 44 and the needle, in a reasonably taut condition sufiicient to prevent fouling.

A thread-breaking mechanism 41 to preclude unnatural winding of the needle-thread about the revolving pins of the take-up, is mounted on the head of the sewing machine between the two disks 32 and 33. The device comprises a carrier 43 which is hinged at its lower edge to the frame of the sewing machine. The carrier 48 is formed with arms overhanging each of the take-up disks and extending inside the orbit of travel of the respective thread-engaging pins. Circular channels are and 50 are provided in the respective faces of the take-up disks 32 and 33, and threadbreaking pins 5| and 52 are mounted on the arms of the carrier 48 to project into the channels 39 and 5!! respectively. When thread leading from the supply becomes ensnared or snubbed upon a revolving pin, which condition would ordinarily result in the rapid winding of a mass of thread upon the pin, the interposed thread-breaking pin will intercept the thread and cause it either to be broken or dragged free of the pin, thereby preventing winding.

After the anti-winding device has performed its thread-breaking function it is not improbable that loose thread ends will remain in the takeup, lying across the thread-breaking pins. It is advisable to remove these pieces before rethreading the take-up. To facilitate removal of the thread pieces, the carrier 48 is provided with a hinge 53 at its lower edge by means of which the thread-breaking pins maybe retracted from their operative positions for the purpose of gaining access thereto. A coil spring 54 in the hinge urges the carrier into its retracted or open position, and a latch 55 holds the carrier in its operative position against the action of the spring 5%. To release the carrier it is only necessary to lift the latch 55, at which time the spring 53 will act to swing the carrier downwardly to a horizontal position as shown in dotted lines in Figs. 6 and 7.

Figs. '7 and 8 show a modified form of the thread-breaking device in which the cover-plate as is provided with a hinge connection 56 between it and the sewing machine frame. A latch 5'? holds the cover-plate in its operative position. The axis of the hinge is inclined to the axis of reciprocation of the needle-bar 9 and is also inclined to the horizontal plane of the bed portion i. This enables the cover-plate to fall into an open position when the latch '51 is released. A coil-spring 58 urges the hinged coverplate outwardly against the action of the latch so that when the latter is released the coverplate is given an initial push outwardly, after which the inclination of its hinge causes it to continue opening into its full-open position as shown in dotted lines in Fig. 7.

The thread-breaking elements 5| and 52, the free ends of which, in their operative positions, ride in the annular channels 49 and 50 in the rotary disks 32 and 33 respectively, are'mounted in a carrier 59 which is in turn rigidly secured to the hinged cover-plate 39. The carrier 59 (Fig. 8) is provided with two pairs of parallel, laterally extending ears E36 and El which are apertured to slidably accommodate the thread-breaking elements 5| and 52. The breaking elements are independently mounted, and may, therefore, be independently withdrawn from their operative positions. Gripping heads 62 and 63 are respectively provided on the thread-breaking elements 5| and 52, and coil springs 64 and 65, acting against shoulders 56 and 6'], urge the breaking pins into their operative positions.

It should be noted that when the thread-breaking pins 5| and 52 Operate to prevent winding of the needle-thread upon the revolving, thread-engaging members 34, 35, and 36 of the take-up, broken thread pieces may possibly become entangled on the thread-breaking elements. To remove these pieces either of the breaking elements may be manually withdrawn from the channel in which it rides by sliding it axially in the carrier. The ears 60 and 6| then act to strip the thread from the breaking elements. If the pieces of broken thread otherwise become trapped in the take-up, the entire cover-plate, supporting the breaking elements and their carrier, may be swung open as described above to permit the operator to gain access to the take-up mechanism.

Variations and modifications may be made in the constructions disclosed above which remain within the purview of the invention, and portions of the improvement may be used without others.

Having thus set forth the nature of the invention, what I claim herein is:

1. In a sewing machine having stitch-forming mechanism including a reciprocatory thread-carrying needle, a rotary needle-reciprocating shaft, and a needle-thread tension device for placing a frictional drag upon the needle-thread, in combination, a pair of revoluble needle-thread takeup members having different radii of revolution about fixed spaced parallel axes, said take-up members acting upon the needle-thread between the said tension device and needle and with the take-up member having the smaller radius of revolution being disposed to engage the needlethread first along the line of flow of thread from the tension device to the needle, said take-up members being arranged with respect to said tension device to engage successive portions of the needle-thread in the direction of lead of thread from the tension device to the needle at the time of their approach to stitch-setting positions thereby to establish a frictional drag upon the thread countering that of the tension device and supplementing the action of the take-up in pulling a suppl of thread through the tension device, and driving connections with said rotary needlereciprocating shaft for revolving said take-up members at uniform angular velocities and at different frequencies.

2. In a sewing machine having stitch-forming mechanism including a reciprocatory threadcarrying needle, a rotary needle-reciprocating shaft, and a needle-thread tension device for placing a frictional drag upon the needle-thread, in

thread second in series after the first member I along the lead of the thread from said tension device to said needle, said second thread-engaging member being arranged to engage the needlethread in the direction of lead of thread from the tension to the needle at the time of the approach 75 of the thread-engaging members to the point at which the needle penetrates the work, actuating mechanism for rotating said take-up members, and a stationary thread guide disposed between the take-up and the needle, said guide being spaced horizontally from the said second threadengaging member to provide a substantially horizontal slack-consuming thread-limb therebetween at the point in the stitch-forming cycle at which the descending needle enters the work.

3. In a sewing machine having stitch-forming mechanism including a reciprocatory thread-carrying needle, a rotary needle-reciprocating shaft, a needle-thread tension device for placing a frictional drag upon the needle-thread, and worl feeding mechanism for passing the work beneath the needle, in combination, a rotary needlethread take-up interposed between the tension device and the needle along the lead of thread therebetween, said take-up including a first revoluble thread-engaging member having a fixed axis of revolution, a second revoluble threadengaging member having a fixed axis of revolution horizontally spaced along the line of workfeeding from the axis of reciprocation of said needle, the horizontal distance of the center of revolution of the second thread-engaging member from the axis of reciprocation of the needle being such that substantially all of the orbit of revolution of said second rotary thread-engaging member lies to one side thereof, said second thread-engaging member being arranged to engage the needle-thread in the direction of lead of thread from the tension device to the needle at the time of the approach of the thread-engaging member to the point at which the needle penetrates the work on its descending stroke, driving connections with said needle-reciprocating shaft for revolving said thread-engaging members and a stationary thread-guide between the takeup and the needle, said guide being spaced horizontally from the axis of revolution of said second thread-engaging element to lie substantially along the axis of reciprocation of said needle.

4. In a sewing machine having a rotar takeup including at least one revoluble thread-engaging member, an anti-winding device for preventing winding of the needle-thread upon said revoluble thread-engaging member, comprising, a thread-breaking element operative to break the thread between the thread-supply and the threadengaging member when abnormal winding of the thread occurs about the latter, a mounting for positioning said thread-breaking element within the orbit of movement of said thread-engaging member, and means providing manually selectable operative and inoperative positions for said thread-breaking element, and yielding means for maintaining the breaking-element in its operative position.

5. In a sewing machine having a rotary takeup including at least one revoluble thread-engaging member, an anti-winding device, comprising, a thread-breaking element operative to prevent abnormal winding of the needle-thread upon the revolving thread-engaging member, a carrier for positioning said thread-breaking element within the orbit of movement of said thread-engaging member, means associated with said carrier and breaking element for selectively positioning the latter in either an operative or inoperative position, and releasable means for holding said breaking element in its operative position.

6. In a sewing machine having a rotary takeup including at least one revoluble thread-engaging member, an anti-winding device for preventing winding of the needle-thread upon the said revolving thread-engaging member, comprising, a thread-breaking element operative to break the thread-limb leading from the supply when abnormal thread-winding occurs about the thread-engaging member, a carrier for said thread-breaking element within the orbit of movement of said thread-breaking member, a hinge connection between said carrier and the sewing machine providing for selective operative and inoperative positions of said thread-breaking element, and releasable means for maintaining said thread-breaking pin in its operative position.

'7. In a sewing machine having a rotary take-up comprising a pair of rotar elements having spaced axes of rotation and at least one orbitally movable thread-engaging member carried by each of said rotary elements, a thread-breaking element associated with each rotary element and operative to prevent abnormal Winding of the thread upon the thread-engaging members, a carrier for said thread-breaking elements for positioning the latter within the respective orbits of said thread-engaging members, connecting means between the sewing machine and the carrier for providing selective operative and inoperative positions for said thread-breaking elements and releasable means for holding said thread-breaking elements in their operative positions.

8. In a sewing machine having a reciprocatory needle-bar and a rotary needle-thread take-up mechanism including an orbitally movable threadengaging member, an anti-winding device for preventing abnormal winding of the thread upon the thread-engaging member of the take-up, said device comprising a thread-breaking element operative to break the thread when abnormal winding occurs, a carrier for said thread-breaking element for positioning the latter adjacent the path of the thread-engaging member, and a hinge connection between said carrier and the sewing machine providing for selective operative and inoperative positions of said thread-breaking element, the axis of the hinge forming an acute angle with the line of reciprocation of the said needlebar.

9. In a sewing machine having a substantially horizontal bed-portion and a rotary needlethread take-up mechanism including an orbitally movable thread-engaging member, an antiwinding device for preventing abnormal winding of the thread upon the thread-engaging member of the take-up, said device comprising a threadbreaking element operative to break the thread when abnormal winding occurs, a carrier for said thread-breaking element for positioning the element adjacent the path of the thread-engaging member, and a hinge connection between said carrier and the sewing machine providing manually selectable operative and inoperative positions of said thread-breaking element, the axis of the hinge being inclined to the bed portion of the sewing machine.

10. In a sewing machine having a rotary takeup mechanism including an orbitally movable thread-engaging member, an anti-winding device for preventing abnormal winding of the thread upon the thread-engaging member, said device comprising a thread-breaking element operative to break the thread when abnormal winding occurs, and a carrier for positioning said thread-breaking element in the vicinity of the orbit of the thread-engaging member, said thread-breaking element being slidably mounted in the carrier to permit the former to be selectively displaced axially between its operative and inoperative positions.

11. In a sewing machine having a rotary takeup mechanism including an orbitally movable thread-engaging member, an anti-winding device for preventing abnormal winding of the thread upon the thread-engaging member, said device comprising a thread-breaking element operative to break the thread when abnormal Winding occurs, and a carrier for positioning said threadbreaking element in the vicinit of the orbit of the thread-engaging member, said thread-breaking element being slidably mounted in the carrier to permit the former to be selectively displaced axially between its operative to an inoperative position, and a hinge connection between said carrier and the sewing machine to permit the carrier and thread-breaking element to be swung outwardly as a unit from the take-up.

12. In a sewing machine having a needlethread take-up mechanism including a pair of coplanar rotary disks having parallel spaced axes of rotation and a thread-engaging member eccentrically disposed on each of said disks, an anti-winding device for preventing abnormal winding of the needle-thread upon the threadengaging members, said device comprisin a thread-breaking element associated with each of said disks and operative to break the needlethread when abnormal winding occurs, a common carrier slidably accommodating each of said thread-breaking elements to enable the latter to be independently shifted from their operative to inoperative positions, and a hinge connection between the carrier and the sewing machine to permit the carrier and thread-breaking elements to be swung outwardl as a-unit away from the take-up mechanism.

13. In a sewing machine having stitch-forming mechanism including a reciprocatory threadcarrying needle, a rotary needle-reciprocating shaft, and a needle-thread tension device for placing a frictional drag upon the needle-thread, in combination, a pair of revoluble needle-thread take-up members having different radii of revolution about fixed horizontally spaced parallel axes, said take-up members acting upon the needle-thread between the said tension device and said needle with the take-up member having the smaller radius of revolution being disposed to engage the needle-thread first along the line of flow of .thread from the tension device to the needle, said take-up members being arranged with respect to said tension device to engage successive portions of the needle-thread in the direction of lead of thread from the tension device to the needle, the horizontal distanc from the center of revolution of the take-up member having the larger radius of revolution to the axis of reciprocation of the needle being such that substantially all of the orbit of revolution of such member lies to one side of the such axis, and a stationary thread-guide between the take-up and the needle, said guide being spaced horizontally from the axis of revolution of that take-up member having the larger radius of revolution so as to lie substantially along the axis of reciprocation of said needle, thereby to provide a substantially horizontal slack-consuming thread-limb between said guide and said second mentioned take-up member at that point in the stitch-forming cycle at which the descending needle enters the work.

ROBERT L. HOFFMEISTER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,191,736 Zonis Feb. 27, 1940 2,321,550 Karr et al June 8, 1943 2,385,960 Zonis Oct. 2, 1945 

